One thing that irks me across most iterations is how much Usagi’s supposed stupidity is played up - she strikes me more as just being an immature, underachieving slacker than actually being dumb. What's your take?
I understand where you're coming from. A lot of the time, it's played out for comedy sake, but I've never been a fan of that type of humor too much.
I feel like the best type of humor when it comes to Usagi revolves more around Usagi's crazy and absurd reactions rather than just characters pointing at her cause she fell on her face. For example, compare any gag of her getting a terrible grade to that really good comedy bit in episode 8 where the monster is quizzing her about Newton and gravity. To the question, "Why do apples fall from trees?" instead of Usagi giving a 'stupid' answer and that being the only joke, she instead talks back at the monster and says the most Usagi thing possible "don't ask me, ask an apple".
Which is not stupid perse, the funny part doesn't come from the fact that it's a stupid thing to say, but it's cause it's an absurd and illogical thing to respond and I feel like that describes Usagi's supposed 'stupidity' pretty well.
I think Usagi isn't so much an idiot as she is oblivious, immature and lazy, like you said. I don't believe she's as stupid as people think. If anything, she's actually quite people smart.
Most likely a lot of the perception of Usagi's supposed stupidity comes from situations where Usagi is put outside of her element and she eventually makes a fool of herself and the other characters call her an idiot.
Tho, it isn't so much stupidity as it is Usagi not being apt to more formal settings, which I'd gathegorize more as her being inept and dorky, while not reacting like other characters would, but instead being way too open for her own good and most a lot of times at the surprise and even discomfort of others.
If Usagi puts her mind to it, she could get better at studying and various other subjects, but she just chooses not to cause she's lazy.